A handheld power tool includes a working device and a powering device. The powering device is for providing a driving force to the working device. When the powering device uses electricity as energy source, such handheld power tool can also be referred to as handheld electric tool. Commonly used handheld power tools are hedge trimmers, grass trimmers, pole saws, etc.
Powering devices using electricity as energy source typically include an electric motor, a circuit board, and a transmission device. However, the arrangement of the electric motor, the circuit board and the transmission device of the traditional powering device is oftentimes unreasonable and/or unsatisfactory for its intended purpose as heat generated by the electric motor and the circuit board during a working process cannot be dissipated in time and thereby can lead to malfunction and damage.
Traditional handheld power tools further include a manipulating device, and the manipulating device is often provided with a trigger for controlling the start of the machine and a manipulating member for speed control. The traditional manipulating member for speed control is disposed just above a handle, which may make it difficult for a user to control the speed while also controlling the trigger.
In order to facilitate transportation and storage, the known handheld power tools often include two detachable long-rod structures. With this arrangement, before using the tool, it is needed to plug the two long-rod structures together to integrally connect the internal transmission shafts contained within the long-rod structures. However, for the traditional plugged structure, the transmission shafts in the long-rod structures each have a large degree of freedom, thus producing a wobble such that the two transmission shafts are not easily combined into an integral structure.
Previous power tools typically include a prime mover, a transmission mechanism, and a tool accessory. The transmission mechanism transmits power outputted by the prime mover to the tool accessory. According to various types of prime movers, power tools can be classified into an engine type tool and an electric tool. For the engine type tool, an oil tank is often equipped therewith for containing a fuel such as gasoline or diesel. For the electric tool, in order to lubricate the transmission mechanism and the tool accessory, an oil tank also is usually equipped therewith.
Commonly used power tools include a lawn mower, a hedge trimmer, a grass trimmer, a snowplow, a chain saw, etc. A chain saw is a type of cutting tool and mainly used for logging operations. In order to cut overhead branches of tree, a chain saw may be provided with a connecting rod, and such a chain saw is usually called as pole saw. A chain saw includes a chain and a guide plate. The guide plate is formed with a guiding groove, and the chain moves in the guiding groove at high-speed to perform a cutting function. A typical chain saw further includes an oil tank, and the oil tank is for supplying oil to the chain so as to achieve lubrication.
After the power tool is used for a period of time, the oil in the oil tank is consumed and the tank may be depleted. Therefore, the user often needs to open a tank cover to refuel the oil tank, which can easily result in the problem of losing the often disassembled tank cover.